Unfortunately, it is simply impossible to determine exactly how wealthy Africa made Britain during the century that you mention. This is because there are too many variables that need to be taken into account. For example, much of Britain's interest in Africa was connected to the Suez Canal. The Canal was important for Britain's trade with India. So, when determining the amount of wealth Africa brought to Britain, do we give it credit for some portion of the commerce that passed through the Suez? How much? As another example, how do we account for the added costs to the British government of conquering Africa and keeping it under control? It is very difficult to determine how much of Britain's military budgets would have been used to keep control of Africa.
Overall, then, it is not possible to know exactly how wealthy Africa made Britain during this time.